In 1963, the State Department was understandably nervous about the longest American spaceflight to date.

When Gordon Cooper climbed into Faith 7 on the morning of May 15, 1963, he was about to embark on the final flight of Project Mercury. Cooper would orbit Earth 22 times in 34 hours—three times longer than Wally Schirra had orbited on the previous Mercury flight—and he would cover most of the globe. Because of this, the U.S. Department of State prepared contingency plans in case Cooper landed in a Communist country. The plans are outlined in a May 1, 1963 letter from Alexis Johnson (Deputy Under Secretary of State for Political Affairs) to McGeorge Bundy (the Deputy Assistant Secretary of Defense for International Security Affairs).

Since search and rescue aircraft would not be allowed to enter the airspace of China, North Vietnam, Cuba, or Laos, intermediaries would ask those governments to return the astronaut and spacecraft. “In the case of Communist China,” wrote Johnson, “the Department plans to enlist the aid of the British Mission in Peiping in addition to the Ambassadorial channel in Warsaw. Similarly, the British Mission in Hanoi, in addition to the International Control Commission at Saigon, will be asked to intervene with North Viet Nam. The Government of Switzerland will be asked to intervene in the case of Cuba.”

The State Department was understandably nervous. Five years earlier, on June 27, 1958, Soviet fighter aircraft had shot down an unarmed American C-118 when it crossed the border near Yerevan. All nine crew members were detained by the Soviets, and they weren’t released until July 7. In September of that year, an unarmed U.S. Air Force C-130 was shot down along the Turkish-Soviet border. A telegram from Moscow indicated that the remains of six crew members had been found. The Soviets claimed no knowledge of the other 11 crew members, which the State Department found difficult to believe. (Post-cold war declassified Soviet documents showed that all crew members died during the crash.) And -- the most famous of these incidents -- U-2 pilot Francis Gary Powers was shot down on May 1, 1960, convicted of spying against the Soviet Union, and sentenced to ten years. (In 1962, Powers was exchanged in a prisoner swap with Soviet agent Vilyam Fisher.)

“Because of the openness and world-wide interest in the type of flight,” wrote Johnson, “it is our judgment that should the astronaut land in Communist territory and be turned over to the governmental authorities he will be returned to the United States. However, little hope is held for the return of the spacecraft.”

Fortunately, Cooper’s capsule splashed down near Midway Island, just four miles from the USS Kearsarge.